Saccharothrix luteola sp. nov., a novel cellulose-degrading actinobacterium isolated from soil and emended description of the genus Saccharothrix.

Abstract

A novel cellulose-degrading actinobacterium, designated strain NEAU-S10T, was isolated from soil collected from Chifeng, Inner Mongolia Autonomous Region, PR China, and characterized using a polyphasic approach. Pairwise similarity of the 16S rRNA gene sequence showed that strain NEAU-S10T was a representative of Saccharothrix and was closely related to Saccharothrix carnea NEAU-yn17T (99.2 %), Saccharothrix saharensis SA152T (99.0 %), Saccharothrix texasensis DSM 44231T (98.5 %) and Saccharothrix xinjiangensis NBRC 101911T (98.5 %). Physiological and chemotaxonomic characteristics of the strain further supported its affiliation to the genus Saccharothrix. The whole-cell sugars contained galactose, ribose and mannose. The polar lipids contained diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The predominant menaquinones were MK-9(H0), MK-9(H2), MK-9(H4) and MK-10(H4). The major fatty acids were iso-C16 : 0, C16 : 0, anteiso-C17 : 0, iso-C15 : 0 and iso-C17 : 0. The genomic DNA G+C content was 71.8 mol%. The levels of digital DNA-DNA hybridization between isolate and S. carnea NEAU-yn17T, S. saharensis SA152T and S. texasensis DSM 44231T were 40.1 % (37.6-42.6 %), 38.soap8 % (36.3-41.3 %) and 44.8 % (42.2-47.3 %) and the ANI values between them were determined to be 90.2, 89.8 and 91.7 %, the results indicated that strain NEAU-S10T could be distinguished from its reference strains. The assembled genome sequence of strain NEAU-S10T was found to be 10 305 394 bp long. The NCBI Prokaryotic Genome Annotation Pipeline (PGAP) revealed 8 994 protein-coding genes. Genomic analysis and Congo red staining test indicated that strain NEAU-S10T had the potential to degrade cellulose. The genomic and phenotypic results indicate that strain NEAU-S10T represents a novel species of the genus Saccharothrix, for which the name Saccharothrix luteola sp. nov. is proposed, with NEAU-S10T (=CCTCC AA 2020037T=JCM 34800T) as the type strain.